Recombinant Human IGFBP-1

Recombinant Human IGFBP-1 is used in research applications to study its regulatory effects on insulin-like growth factors, its role in metabolic and cardiovascular physiology, and its impact on cell signaling, regeneration, and disease models.

IGFBP-1 (Insulin-like Growth Factor Binding Protein-1) binds IGF-I and IGF-II, modulating their bioavailability and activity in various tissues. This protein is highly expressed in the liver, decidua, and kidneys, and is the most abundant IGFBP in amniotic fluid. Its serum levels fluctuate with nutritional status, being lowest after meals.

Key research applications include:

• Metabolic Regulation: IGFBP-1 influences insulin sensitivity, glucose metabolism, and insulin secretion. Increasing circulating IGFBP-1 levels has been shown to improve insulin sensitivity, promote nitric oxide production, lower blood pressure, and protect against atherosclerosis in animal models.
• Cell Signaling and Regeneration: IGFBP-1 promotes β-cell regeneration by facilitating transdifferentiation, and is involved in liver-bone endocrine signaling that affects osteoclastogenesis and bone resorption.
• Cardiovascular Research: IGFBP-1 enhances endothelial nitric oxide synthase (eNOS) activity, contributing to vasodilation and cardiovascular protection independently of IGF signaling.
• Diabetes and Wound Healing Models: IGFBP-1 modulates the hypoglycemic effects of IGF-I and insulin, and has been shown to enhance IGF-I action in wound healing models, supporting its use in studies of tissue repair and diabetes.
• Female Reproductive Physiology: IGFBP-1 is important in the regulation of menstrual cycles and reproductive function, making it relevant for reproductive biology research.

Experimental uses include bioassays, cell culture studies, and in vivo models to dissect IGF signaling pathways, investigate metabolic and cardiovascular disease mechanisms, and explore therapeutic interventions for diabetes, atherosclerosis, and tissue regeneration.

In summary, recombinant human IGFBP-1 is a versatile tool for investigating IGF-related signaling, metabolic regulation, cardiovascular physiology, and regenerative processes in both basic and translational research contexts.

Yes, recombinant human IGFBP-1 can be used as a standard for quantification or calibration in ELISA assays, provided that the recombinant protein is compatible with the specific ELISA kit and detection system you are using.

Key Points:

• Recombinant IGFBP-1 as Standard: Many commercial ELISA kits for human IGFBP-1 use recombinant human IGFBP-1 as the calibrator or standard (e.g., ab213789, RayBiotech, R&D Systems, BosterBio). The recombinant protein is typically expressed in mammalian systems (such as NS0) and matches the native human sequence, ensuring accurate quantification.

• Compatibility: The recombinant protein should be recognized by both the capture and detection antibodies in your ELISA system. Most kits are validated for both natural and recombinant IGFBP-1, but always check the kit’s datasheet or manual for confirmation.

• Validation: For best results, the recombinant standard should be serially diluted in the same matrix as your samples (e.g., assay buffer, serum, or plasma) to generate a standard curve. This curve is then used to interpolate the concentration of IGFBP-1 in your samples.

• Precision and Accuracy: Using a recombinant standard allows for precise and reproducible quantification, especially if the protein is carrier-free and highly purified.

Recommendations:

• Confirm that the recombinant IGFBP-1 you are using matches the immunogen sequence and epitopes recognized by your ELISA kit.
• Follow the manufacturer’s instructions for preparing the standard curve.
• Include appropriate controls and replicates to ensure assay accuracy.

In summary, recombinant human IGFBP-1 is suitable for use as a standard in ELISA assays for quantifying IGFBP-1, as long as compatibility with your specific kit is confirmed.

Recombinant Human IGFBP-1 has been validated for diverse applications across multiple research domains, reflecting its significance as a functional tool in molecular and cellular biology.

Bioactivity and Protein-Protein Interaction Studies

The primary validated application involves bioactivity assays, where recombinant IGFBP-1 demonstrates its functional capacity to bind insulin-like growth factors (IGFs). Functional validation typically employs ELISA-based approaches, measuring the protein's binding ability to IGF ligands across defined concentration ranges. This bioactivity validation is critical for confirming that the recombinant protein maintains the biological properties of the native molecule, including its ability to modulate IGF signaling through direct protein-protein interactions.

Cell Biology and Endothelial Function

Research has extensively employed recombinant IGFBP-1 in cell biology studies using human umbilical vein endothelial cells (HUVECs). Specific validated applications include Matrigel tube formation assays to assess angiogenic properties, endothelial cell proliferation assays, and cytodex bead assays to evaluate endothelial sprouting capacity. These studies demonstrated that recombinant IGFBP-1 at concentrations of 500 ng/mL enhances endothelial tube formation and significantly increases endothelial cell proliferation within one hour of incubation.

Immunological Research

The protein has been validated for use in immunological research applications, including Western blotting, immunohistochemistry, immunofluorescence, immunoprecipitation, flow cytometry, and ELISA-based detection methods. These applications leverage the protein's structural integrity and the presence of affinity tags for convenient detection and purification.

Therapeutic Development and Disease Modeling

Recombinant IGFBP-1 serves as an investigative tool in therapeutic development, particularly for conditions involving dysregulated IGF signaling pathways. Research has validated its use in studying cardiometabolic pathophysiology, where overexpression studies in cellular models have demonstrated effects on vascular insulin sensitization, glucose tolerance, and insulin sensitivity through interactions with cell surface integrin receptors. Additionally, functional studies have explored IGFBP-1's role in cancer biology, where it promotes invasion and migration in gastric cancer cell models.

Bioassay Applications

The protein has been validated in bioassay formats for investigating cellular responses, including studies on β-cell regeneration and bone resorption pathways. These applications utilize the protein's biological activity to model physiological processes relevant to metabolic and skeletal homeostasis.

To reconstitute and prepare Recombinant Human IGFBP-1 protein for cell culture experiments, dissolve the lyophilized protein at a concentration of 100 μg/mL in sterile PBS or 0.1–0.5 mg/mL in sterile distilled water, depending on your experimental requirements and the specific formulation of the protein.

Protocol and Best Practices:

• Centrifuge the vial briefly (6000–10,000 rpm for 30 s) before opening to ensure all powder is at the bottom.
• Add sterile PBS or distilled water to achieve the desired concentration (commonly 100 μg/mL for cell culture applications). If using water, ensure it is ultrapure (18 MΩ·cm).
• Gently mix by pipetting up and down or swirling. Avoid vigorous vortexing or pipetting, which can denature the protein.
• Aliquot the reconstituted protein to avoid repeated freeze-thaw cycles, which can reduce activity and stability.
• Storage: After reconstitution, store aliquots at 4 °C for short-term use (up to 1 week) or at −20 °C to −80 °C for long-term storage. Avoid repeated freeze/thaw cycles.
• Carrier protein: If your application tolerates it, adding a carrier protein (e.g., BSA at 0.1%) can improve stability, but use carrier-free IGFBP-1 if BSA may interfere with your assay.
• Working concentration: For cell culture bioassays, typical working concentrations range from 0.1–0.6 μg/mL, but optimize based on your cell type and experimental design.

Summary Table: Preparation Steps

Additional Notes:

• Always consult the specific product datasheet for formulation details and recommended diluents, as some preparations may require PBS while others are compatible with water.
• For cell culture, ensure all reagents are sterile and endotoxin levels are suitable for your application (typically <0.1 EU/μg).
• If using for ELISA or other analytical assays, follow the buffer recommendations provided in the kit protocol.

This protocol ensures optimal solubility, stability, and biological activity of recombinant IGFBP-1 for cell culture experiments.